This program encompasses investigations on the mechanical properties of myocardium; the mechanisms of adaptation of the whole heart to acute and chronic forms of experimental disease; the chronic effects of cardiovascular drugs on cardiac performance; characterization of the functional and metabolic properties of the fetal and neonatal heart; the energetics of the coronary circulation; the hormonal regulation of lipolysis and triglyceride uptake from lipoproteins at the cellular level; the biochemistry of the sympathetic nervous system relative to mechanisms involving cyclic AMP and the role of calcium; models for the beta adrenergic receptor; structure-function correlations in the pulmonary vascular bed; clinical assessment of ventricular function by invasive and non-invasive methods; and studies on the reversibility of myocardial abnormalities following cardiac surgery. The techniques of physiology, muscle biochemistry, molecular pharmacology, electron-microscopy, pathology, radiology, and clinical cardiology are employed in these investigations. Bibliographic references: Ross, J., Jr.: Section X11, No.556-563. Acquired valvular heart disease, pp 958-980. In Textbook of Medicine, fourteenth Edition. Ed. Paul B. Beeson and Walsh McDermott, W.B. Saunders Company, Philadelphia, 1975; Venter, J.S., Ross, J., Jr., and Kaplan, N.O.: Lack of detectable change in cyclic amp during the cardiac inotropic response to isoproterenol immoblized on glass beads. Proc. Nat. Acad. Sci., U.S.A., 72, No. 3 824-828, 1975.